1. Field of the Invention
This invention is directed to projectile structured to be discharged from a firearm and comprising separable nose and tail portions and an interconnecting interface. The interface is structured to facilitate concurrent, synchronization rotation of the nose portion, the interface and the tail portion as the projectile travels through the bore of the firearm and as it exits therefrom. The interface is dimensioned and disposed to define a reduced contact area of the projectile body with the rifling or interior surface of the barrel of the firearm.
2. Description of the Related Art
The latter part of the twentieth century brought environmental concerns into the ammunition field. The resulting changes included the United States military reducing the use of copper jacketed lead projectiles in an effort to reduce lead contamination. In addition, Oak Ridge National Laboratory was given the task of finding a lead free alternative to be used in the structuring and design of firearm projectiles. This research led to the development of a tungsten/tin compound known in the industry as “Green Bullet”. Practical application and formation of this material involves tungsten powder bound together with tin or nylon and inserted into a jacket in place of the formerly used lead material. The performance characteristics of the resulting projectiles are equivalent to conventional lead filled projectiles but involve a significantly higher cost of production.
Accordingly, with the intended elimination or reduction in the use of lead in firearm projectiles there is a significant need in the firearm industry for a projectile capable of being tailored to assume various densities while distinguishing the weight of the projectile from its size. Currently, NATO 5.56 mm M855(SS109) projectiles comprise a steel/lead core placed in a copper jacket which weighs 62 grains. Ideally, an improved projectile could be proposed and developed having the same physical dimensions but having an increased weight, of for example 107 grains or a 72 percent weight increase. In order to achieve the same weight utilizing the conventional jacketed lead projectile a significant change in the length of the projectile would have to be assumed. This additional length would decrease the space available for gun powder thereby reducing the propelling charge of the projectile. Moreover, the increased length in order to accomplish the desired increase in weight would also require a different rifling twist rate on the interior barrel surface of the firearm.
Accordingly, a desired and proposed improvement in projectiles would comprise an increase in the weight of the projectile with no decrease in case volume. Moreover, this would result in increased terminal energy which translates into energy delivered to the target upon impact of the projectile. More specifically, greater density means improved ballistic coefficient to the extent that an improved and proposed projectile would lose less of its initial velocity at long range target distances than jacketed lead or steel projectiles. As a result, an improved projectile would have increased accuracy as well as greater terminal energy and penetration characteristics.
Furthermore, an increased need in the firearms industry for an improved projectile would preferably involve a proposal which eliminates the use of a jacketed projectile. In contrast, a proposed projectile would have an exterior surface which engages the rifling along a reduced contact area as compared to conventional projectiles. Additional improvements may involve the use of a copper alloy in forming portions of the exterior surface of the projectile body. In the alternative, the exterior surface defining the contact area of the improved projectile could be made from other alloys or polymers. Therefore the design and structuring of a proposed projectile would result in a contact area thereon which would be significantly less than a traditional jacketed lead bullet. Accordingly, by reducing the contact area of the projectile, barrel friction would be significantly reduced. In turn, heat buildup would be reduced and the barrel performance during sustained fire of such projectiles would be greatly improved. Other advantages would involve the increase in barrel life of the firearm and reduced fouling. Additional performance characteristics of a proposed and improved projectile would provide significantly greater penetration when impacting hard targets such as armor, glass, vehicles, etc. than conventional jacketed lead projectiles. Additional physical characteristics of a proposed projectile would provide capabilities of delivering supplemental payloads while offering controlled fragmentation against soft targets (humans/animals).
Finally, the practical application and manufacturing associated with such a proposed preferred projectile in quantities adequate for the military and law enforcement needs would be significantly reduced due to the relative simplicity of the non-jacketed projectile, as proposed. Moreover, projectiles could be produced at a modest cost, especially as compared to the “Green Bullet” technology as briefly described above, while enabling the projectiles to be produced in all calibers generally ranging from .17 through 50 BMG while significantly improving the performance of all small caliber weapons systems.